Microwave and wireless connections play an increasingly important role in the backhaul connectivity. In particular, a two-transmitter two-receiver (2T2R) digital microwave radio in one enclosure provides advantages such as increased capacity and coverage of microwave radios and reduced cost over the traditional one-transmitter one-receiver (1T1R) system design. A typical 2T2R system includes an antenna coupling unit with integrated circulators and isolators, which is also referred to as “circulator plate”. The conventional antenna coupling devices have a fixed structure and layout, which makes it difficult for the same circulator plate to support a 2T2R digital microwave radio with flexible coupling factors and reduced insertion loss.